Abhisek Mudgal

On-Road Evaluation of Emission Impacts of Roundabouts

Reduced emissions and improved air quality are typically attributed to the use of roundabouts rather than traditional stop or signal control. Roundabouts are expected to reduce emissions as a result of reduced delays and stops. However, roundabouts slow all vehicles to speeds at which emissions may be higher, while signals stop and delay only a portion of vehicles. Roundabouts may also increase the amount of acceleration and deceleration for all vehicles. Because emissions are correlated to these modal events, their impacts should be considered in the evaluation of roundabouts. An on-road assessment of the emission impacts of two roundabouts compared with other types of traffic control was conducted with a vehicle instrumented with a portable emissions monitor. Emissions were measured along two corridors in Woodbury, Minnesota, with two drivers. The corridor at Bailey Road had two four-way stop-controlled intersections, one roundabout, and one signal. The corridor at Lake Road had one four-way stop, one roundabout, and one signal. Intersection spacing and traffic parameters were similar along each corridor. Emissions were compared for sections 750 ft upstream and 750 ft downstream of each intersection. Traffic conditions during data collection along both corridors were uncongested. Average emission rate by driver was compared for the three types of traffic control. Results suggested that emissions were highly dependent on driver behavior. The roundabouts did not necessarily have lower emissions than traditional stop or signal control.

Neuro-fuzzy approach to predictive modeling of emissions from biodiesel powered transit buses

Abstract The rise in freight passenger transportation is responsible for air pollution, green house gas emissions (especially CO2) and high fuel demand. New engine technology and fuels are discovered and tested throughout the world. Biodiesel, an alternative for diesel, has been seen as a solution. However, the amount of emissions generated by a biodiesel fueled vehicle has not been understood well since most research studies of this kind reported in the literature were conducted in the laboratory. In the present study, emissions (NOx, HC, CO, CO2 and PM) were measured from biodiesel fueled transit buses using an on-road emissions measuring device known as the Portable Emissions Measurement System (PEMS). On-road study is important in terms of understanding the amount of emissions generated under the real traffic and environmental conditions. Emissions were measured on buses fueled with regular diesel (B0), B10 blend (10% biodiesel + 90% diesel) and B20 blend (20% biodiesel + 80% diesel). This paper demon...

In-Use Fuel Economy of Hybrid-Electric School Buses in Iowa

ABSTRACT Although it is much safer and more fuel-efficient to transport children to school in buses than in private vehicles, school buses in the United States still consume 822 million gal of diesel fuel annually, and school transportation costs can account for a significant portion of resource-constrained school district budgets. Additionally, children in diesel-powered school buses may be exposed to higher levels of particulates and other pollutants than children in cars. One solution to emission and fuel concerns is use of hybrid-electric school buses, which have the potential to reduce emissions and overall lifecycle costs compared with conventional diesel buses. Hybrid-electric technologies are available in the passenger vehicle market as well as the transit bus market and have a track record indicating fuel economy and emissions benefits. This paper summarizes the results of an in-use fuel economy evaluation for two plug-in hybrid school buses deployed in two different school districts in Iowa. Each school district selected a control bus with a route similar to that of the hybrid bus. Odometer readings, fuel consumption, and maintenance needs were recorded for each bus. The buses were deployed in 2008 and data were collected through May 2010. Fuel consumption was calculated for each school district. In Nevada, IA, the overall average fuel economy was 8.23 mpg for the hybrid and 6.35 mpg for the control bus. In Sigourney, IA, the overall average fuel economy was 8.94 mpg for the hybrid and 6.42 mpg for the control bus. The fuel consumption data were compared for the hybrid and control buses using a Wilcoxon signed rank test. Results indicate that fuel economy for the Nevada hybrid bus was 29.6% better than for the Nevada control bus, and fuel economy for the Sigourney hybrid bus was 39.2% higher than for the Sigourney control bus. Both differences were statistically significant. IMPLICATIONS The results of the research presented in this paper can be readily used by school districts and policy-makers who are interested in purchasing hybrid school buses. Very little information about actual on-road fuel consumption or costs is available. Because the cost of a hybrid bus can be significantly more than the cost of a conventional bus, the information provided in this paper can be very useful for an agency to determine the costs and benefits of a hybrid bus. The information is also useful to researchers who are studying hybrid school and transit buses.

Vehicle Consumer Complaint Reports Involving Severe Incidents: Mining Large Contingency Tables

According to 2010–2014 Fatality Analysis Reporting System (FARS) data, nearly 6.35% of fatal crashes happened as a result of vehicles’ pre-existing manufacturing defects. The National Highway Traffic Safety Administration’s (NHTSA) vehicle complaint database incorporates more than 1.37 million complaint reports (as of June 1, 2017). These reports contain extended information on vehicle-related disruptions. Around 5% of these reports involve some level of injury or fatalities. This study had two principal objectives, namely (1) perform knowledge discovery to understand the latent trends in consumer complaints, and (2) identify clusters with high relative reporting ratios from a large contingency table of vehicle models and associated complaints. To accomplish these objectives, 67,201 detailed reports associated with injury or fatalities from the NHTSA vehicle complaint database were examined. Exploratory text mining and empirical Bayes (EB) data mining were performed. Additionally, this study analyzed five years (2010–2014) of FARS data to examine the research findings. Results show that major vehicular defects are associated with air bags, brake systems, seat belts, and speed controls. The EB metrics identified several key ‘vehicle model with major defect’ groups that require more attention. This study demonstrates the applicability of consumer complaints in identifying major vehicular defects as well as key groups of ‘vehicle model with major defect.’ The findings of this study will provide a significant contribution to the reduction of crashes from vehicle-related disruptions. The research presented in this paper is crucial given the ongoing advancement of connected and automated vehicle technologies.

Comparison of VSP profiles for three types of intersection control and implications for emissions

Roundabouts have generally been considered to have lower emissions as compared to signal controlled and 4-way stop-control intersections since they improve traffic flow and average speed. However, roundabouts slow all vehicles to speed ranges where emissions are higher, while signals stop and delay only a portion of vehicles. Roundabouts have the potential to increase the amount of acceleration and deceleration for all vehicles. Emissions are correlated to these modal events, therefore the impacts should be considered in the evaluation of roundabouts. Vehicle activity (instantaneous speed and acceleration) are key inputs to modal emission models such as the US Environmental Protection Agencys MOVES. The objective of this paper was to compare the vehicle activity of a roundabout to 4-way stop control and signal controlled intersections. The paper presents result of a study which collected second-by-second vehicle activity on-road along a corridor in Urbandale, Iowa. Vehicle activity for the three different types of traffic control was compared.

Leveraging the Value of Land and Landside Access to Fund Port Infrastructure in Texas

This paper introduces port authority transportation reinvestment zones (TRZs), a funding tool created by the Texas Legislature to help fund long-term economic development port projects. TRZs were first introduced in Texas in 2007 as a tool to allow county and municipal governments to raise funds to help pay for transportation improvements using the property tax mechanism. Since then, the legislation has been amended to include other transportation modes, such as transit, rail, and parking facilities. Amendments passed in 2013 introduced the concept of port authority TRZ, which expanded authorized use of the tool to the state’s port authorities and navigation districts. Most of the existing funding tools available to Texas ports focus on the development of infrastructure within port property. Port authority TRZs complement existing funding sources by providing a funding tool flexible enough to fund port projects both inside and outside port property. Port authorities can take advantage of the TRZ concept to join forces with neighboring local governments and the Texas Department of Transportation to fund landside transportation enhancements that improve port accessibility and the regional economy. Currently, there are four active port authority TRZs in the following locations: Port of Beaumont, Port of Port Arthur, Port of Brownsville, and Sabine-Neches Navigation District. This paper summarizes the legal framework of port authority TRZs, describes the role that these TRZs play in port funding and finance, and presents highlights of the port authority TRZs that have already been established throughout the state.

Modelling creep and recovery response of asphalt binders using generalized burgers model

Abstract Appropriate modeling creep and response of asphalt binders can save time, and resources and efforts required for multiple experimentations. Creep compliance master-curves were obtained from short duration creep experiments on 10 different asphalt binders each at 0.1 and 3.2u2009kPa stress levels. It was shown that, a four Kelvin-element generalized Burger’s model could closely approximate creep and recovery response at any combination of loading and unloading cycle. A single run of dynamic shear rheometer used for conducting short time creep experiments at different temperatures, can be adequate for modeling creep and recovery response of asphalt binders.